1. (n.) The act of obligating.

2. (n.) That which obligates or constrains; the binding power of a promise, contract, oath, or vow, or of law; that which constitutes legal or moral duty.

3. (n.) Any act by which a person becomes bound to do something to or for another, or to forbear something; external duties imposed by law, promise, or contract, by the relations of society, or by courtesy, kindness, etc.

4. (n.) The state of being obligated or bound; the state of being indebted for an act of favor or kindness; as, to place others under obligations to one.

5. (n.) A bond with a condition annexed, and a penalty for nonfulfillment. In a larger sense, it is an acknowledgment of a duty to pay a certain sum or do a certain things.

accountability accounts payable accounts receivable act of grace act of kindness affair agreement allegiance amount due appreciation appreciativeness aptitude aptness arrearage assigned task attempt bad debts benefaction benefit benevolence benignity bill bills blessing bond borrowing boundary condition bounden duty burden business call call of duty catch cause chance charge charges chits clause coaction commitment committal compulsatory compulsion compulsiveness compulsoriness compulsory condition constraint contingency contract courtesy covenant deal debt dedication deference demand devoir devotion donnee due dues duress duties and responsibilities duty effort enforcement engagement enterprise escalator clause escape clause escape hatch ethics eventuality favor fealty financial commitment fine print floating debt forcing funded debt given good deed good offices good turn grace gratefulness gratitude grounds homage imperative imperious indebtedness indebtment inevitability irresistibility joker kicker kind deed kind offices kindly act kindness labor of love liability liableness likelihood likeliness limiting condition line of duty loyalty mandatedness mandatoriness maturity mercy mission mitzvah must national debt necessariness necessitation necessitude necessity need obligatoriness obligatory obligement office onus operation ought outstanding debt parameter part place plan pledge possibility preengagement prerequisite probability program project promise proneness proposition provision provisions proviso public debt recognizance required requirement requisite respect responsibility restraint right saving clause score self-imposed duty sense of obligation service sine qua non small print specification stipulation string task terms thankfulness trust turn ultimatum uncollectibles understanding undertaking unfulfilled pledge venture verbal agreement weakness whereas work